The present disclosure relates to a monitoring device for monitoring the functional capability of an accumulator for electrical energy of a battery. In addition, the present disclosure relates to a method for monitoring the functional capability of an accumulator for electrical energy of a battery. Furthermore, the present disclosure relates to a battery system having a battery and a discharge device. Finally, the present disclosure relates to a discharge device for at least one battery which has at least one accumulator for electrical energy, wherein the accumulator is embodied with two connecting elements which are connected in an electrically conductive fashion to connecting contacts of the battery, wherein the discharge device has a discharging current path for conducting a discharging current between the connecting elements and a discharging switch for closing the discharging current path.
Monitoring devices and methods for monitoring the functional capability of an accumulator for electrical energy of a battery and battery systems having a discharge device and discharge devices are generally known. In addition, motor vehicles which can be driven at least partially or completely electrically and have battery systems for storing drive energy are known. Monitoring devices are often provided in battery management systems and monitor, for example, electrical parameters of at least one accumulator for electrical energy. If the result of the monitoring is that the accumulator is not functionally capable, the accumulator can, for example, be exchanged. In order to be able to exchange the accumulator, the content of electrical energy thereof has to be reduced by the discharge device to such an extent that the accumulator can be exchanged without damage to the battery and without operators being placed at risk.
With the known devices and methods it is also possible to detect damage to the accumulator, with the result that the energy which is contained in the accumulator can be at least reduced in order to avoid resulting damage. However, this damage is detected exclusively on the basis of its effects, for example changing properties of the accumulator. Causes which can lead to damage to the accumulator are not detected.
However, if damage is not detected until it affects the accumulator and the properties thereof, it can, however, be too late to avoid catastrophic resulting damage to the accumulator. For example, the accumulator may overheat greatly and cause fires, for example in the motor vehicle. In addition, the heating of the accumulator can lead to a rise in pressure within the accumulator and to an explosion of the accumulator. In order to prevent the accumulator exploding, a large number of accumulators have pressure valves so that an overpressure can be discharged. However, in this case poisonous gases or liquid acid can escape from the accumulator and damage objects directly or through the formation of explosive flames, or can even injure people.
This resulting damage can occur directly after the appearance of the damage or not until hours, days or weeks later. In addition to damage due to an accident, faults due to transportation or fabrication can also give rise to the specified resulting damage.